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1.
Acta Ortop Mex ; 38(3): 179-187, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38862148

RESUMO

Arthrofibrosis is a challenging complication associated with knee injuries in both children and adults. While much is known about managing arthrofibrosis in adults, it is necessary to understand its unique aspects and management strategies in the pediatric population. This paper provides an overview of arthrofibrosis in pediatric orthopedic surgery, focusing on its causes, implications, classifications, and management. This paper is a comprehensive review of the literature and existing research on arthrofibrosis in pediatric patients. Arthrofibrosis is characterized by excessive collagen production and adhesions, leading to restricted joint motion and pain. It is associated with an immune response and fibrosis within and around the joint. Arthrofibrosis can result from various knee injuries in pediatric patients, including tibial spine fractures, ACL and PCL injuries, and extra-articular procedures. Technical factors at the time of surgery play a role in the development of motion loss and should be addressed to minimize complications. Preventing arthrofibrosis through early physical therapy is recommended. Non-operative management, including dynamic splinting and serial casting, has shown some benefits. New pharmacologic approaches to lysis of adhesions have shown promise. Surgical interventions, consisting of arthroscopic lysis of adhesions (LOA) and manipulation under anesthesia (MUA), can significantly improve motion and functional outcomes. Arthrofibrosis poses unique challenges in pediatric patients, demanding a nuanced approach that includes prevention, early intervention with non-operative means, and improvements in surgical techniques. Modern pharmacological interventions offer promise for the future. Customized interventions and research focused on pediatric patients are critical for optimal outcomes.


La artrofibrosis es una complicación difícil asociada con lesiones de rodilla tanto en niños como en adultos. Si bien se sabe mucho sobre el manejo de la artrofibrosis en adultos, es necesario comprender sus aspectos únicos y estrategias de manejo en la población pediátrica. Este documento proporciona una visión general de la artrofibrosis en la cirugía ortopédica pediátrica, centrándose en sus causas, implicaciones, clasificaciones y manejo. Este documento es una revisión completa de la literatura y la investigación existente sobre artrofibrosis en pacientes pediátricos. La artrofibrosis se caracteriza por una producción excesiva de colágeno y adherencias, lo que conduce a un movimiento articular restringido y dolor. Se asocia con una inmunorrespuesta y fibrosis dentro y alrededor de la articulación. La artrofibrosis puede ser el resultado de varias lesiones de rodilla en pacientes pediátricos, incluyendo fracturas de columna tibial, lesiones de LCA y LCP, y procedimientos extraarticulares. Los factores técnicos en el momento de la cirugía desempeñan un papel en el desarrollo de la pérdida de movimiento y deben abordarse para minimizar las complicaciones. Se recomienda prevenir la artrofibrosis a través de la fisioterapia temprana. La gestión no operativa, incluyendo el empalme dinámico y la fundición en serie, ha mostrado algunos beneficios. Los nuevos enfoques farmacológicos a la lisis de adherencias han demostrado ser prometedores. Las intervenciones quirúrgicas, consistentes en lisis artroscópica de adherencias (LOA) y manipulación bajo anestesia (MUA), pueden mejorar significativamente el movimiento y los resultados funcionales. La artrofibrosis plantea desafíos únicos en los pacientes pediátricos, exigiendo un enfoque matizado que incluye prevención, intervención temprana con medios no operatorios y mejoras en las técnicas quirúrgicas. Las intervenciones farmacológicas modernas ofrecen una promesa para el futuro. Las intervenciones e investigaciones personalizadas centradas en pacientes pediátricos son fundamentales para obtener resultados óptimos.


Assuntos
Fibrose , Procedimentos Ortopédicos , Humanos , Criança , Procedimentos Ortopédicos/métodos , Complicações Pós-Operatórias/etiologia , Traumatismos do Joelho/cirurgia , Aderências Teciduais/etiologia , Artropatias/etiologia , Artropatias/cirurgia , Artropatias/terapia , Articulação do Joelho/cirurgia , Articulação do Joelho/patologia
2.
Science ; 385(6716): eadm7966, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39325875

RESUMO

We report the discovery of MED6-189, an analog of the kalihinol family of isocyanoterpene natural products that is effective against drug-sensitive and drug-resistant Plasmodium falciparum strains, blocking both asexual replication and sexual differentiation. In vivo studies using a humanized mouse model of malaria confirm strong efficacy of the compound in animals with no apparent hemolytic activity or toxicity. Complementary chemical, molecular, and genomics analyses revealed that MED6-189 targets the parasite apicoplast and acts by inhibiting lipid biogenesis and cellular trafficking. Genetic analyses revealed that a mutation in PfSec13, which encodes a component of the parasite secretory machinery, reduced susceptibility to the drug. Its high potency, excellent therapeutic profile, and distinctive mode of action make MED6-189 an excellent addition to the antimalarial drug pipeline.


Assuntos
Antimaláricos , Apicoplastos , Diterpenos , Malária Falciparum , Plasmodium falciparum , Animais , Humanos , Camundongos , Antimaláricos/química , Antimaláricos/farmacologia , Apicoplastos/efeitos dos fármacos , Apicoplastos/metabolismo , Modelos Animais de Doenças , Resistência a Medicamentos/genética , Malária Falciparum/tratamento farmacológico , Malária Falciparum/parasitologia , Mutação , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/genética , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Diterpenos/química , Diterpenos/farmacologia
3.
bioRxiv ; 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-38045341

RESUMO

Here we report the discovery of MED6-189, a new analogue of the kalihinol family of isocyanoterpene (ICT) natural products. MED6-189 is effective against drug-sensitive and -resistant P. falciparum strains blocking both intraerythrocytic asexual replication and sexual differentiation. This compound was also effective against P. knowlesi and P. cynomolgi. In vivo efficacy studies using a humanized mouse model of malaria confirms strong efficacy of the compound in animals with no apparent hemolytic activity or apparent toxicity. Complementary chemical biology, molecular biology, genomics and cell biological analyses revealed that MED6-189 primarily targets the parasite apicoplast and acts by inhibiting lipid biogenesis and cellular trafficking. Genetic analyses in P. falciparum revealed that a mutation in PfSec13, which encodes a component of the parasite secretory machinery, reduced susceptibility to the drug. The high potency of MED6-189 in vitro and in vivo, its broad range of efficacy, excellent therapeutic profile, and unique mode of action make it an excellent addition to the antimalarial drug pipeline.

4.
Acta Ortop Mex ; 36(6): 367-372, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37669656

RESUMO

INTRODUCTION: although pediatric orthopedic surgeons worldwide perform scoliosis surgery, the training received is variable and poorly understood. By surveying the European Pediatric Orthopedic Society (EPOS) and the Sociedad Latinoamericana de Ortopedia (SLAOTI), we aim to characterize this variability. MATERIAL AND METHODS: in 2021, we distributed an anonymous online questionnaire to EPOS and SLAOTI. RESULTS: 43% EPOS and 22% SLAOTI perform scoliosis procedures (p < 0.05). 18% EPOS and 2% SLAOTI performed > 35 procedures annually (p < 0.05). 70% EPOS and 27% SLAOTI received formal training in spinal deformity surgery (p < 0.005). CONCLUSIONS: results show significant differences in training and performance of scoliosis procedures between societies.


INTRODUCCIÓN: aunque muchos cirujanos ortopédicos pediátricos alrededor del mundo realizan cirugías para la escoliosis, el entrenamiento es variable y poco conocido. A través de encuestar a la Sociedad Europea de Ortopedia Pediátrica (EPOS) y a la Sociedad Latinoamericana de Ortopedia (SLAOTI) queremos caracterizar esta variabilidad. MATERIAL Y MÉTODOS: distribuimos un cuestionario anónimo en 2021 a los miembros de EPOS y SLAOTI. RESULTADOS: realizan las cirugías de escoliosis 43% de EPOS, en comparación con 22% de SLAOTI (p < 0.05); 18% de EPOS realizó > 35 cirugías al año, en comparación con 2% de SLAOTI (p < 0.05); 70% de EPOS y 27% de SLAOTI recibieron capacitación formal en cirugía de deformidades de la columna (p < 0.005). CONCLUSIONES: los resultados de este estudio subrayan las diferencias en el entrenamiento de las cirugías de escoliosis entre diferentes sociedades.


Assuntos
Cirurgiões Ortopédicos , Ortopedia , Escoliose , Fusão Vertebral , Humanos , Criança , Escoliose/cirurgia , Inquéritos e Questionários , Fusão Vertebral/métodos
5.
J Child Orthop ; 13(4): 371-376, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31489042

RESUMO

PURPOSE: The optimal treatment for late-presenting developmental dysplasia of the hip (DDH) is controversial. High tension forces after hip reduction increase the pressure on the femoral head, potentially causing avascular necrosis. Femoral shortening (FS) is commonly used as a means to decrease the pressure on the femoral head. We examined the effect of FS on the outcomes of patients with late-presenting DDH. METHODS: A total of 645 hips of a late-presenting DDH cohort treated with open reduction and iliac osteotomies were retrospectively reviewed; 328 hips had a FS performed (FS+) and 317 (FS-) had not. The mean age was 3.9 years (sd 1.55). We classified the hips with the Tönnis and International Hip Dysplasia Institute (IHDI) methods; and the Pediatric Outcomes Data Collection Instrument (PODCI), Iowa Hip Score (IHS) and Severin classification as outcome measurements. RESULTS: The FS- group had higher scores in PODCI (median 95 points; interquartile range (IQR) 78 to 91) and IHS (median 91 points; IQR 64 to 88) than the FS+ group (PODCI: median 94 points; IQR 69 to 89 points; IHS: median 89 points; IQR 62 to 87). The mean Severin scores were similar (FS- 2.65; FS+ 2.5; p = 0.93) but the FS- group had higher rates of good and excellent outcomes (FS- 56%; FS+ 41%; p < 0.00001) and lesser dislocation rates (FS- 6%; FS+ 14%; p = 0.16). CONCLUSION: Although FS should be used when a hip cannot be reduced without undue tension, our results indicate that this procedure is not necessarily related to a better outcome. LEVEL OF EVIDENCE: Therapeutic, Level III.

6.
J Child Orthop ; 12(4): 323-330, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30154922

RESUMO

PURPOSE: Patients with late-presenting developmental dysplasia of the hip (DDH) are more likely to require an open reduction. Since many developing countries do not have mandated screening, there continues to be a relatively high incidence of late-presenting DDH. We report the clinical and radiographic outcomes of open reduction in a series of patients who presented late. PATIENTS AND METHODS: This was a retrospective review of 712 hips in 645 patients that underwent open reduction, alone or in combination with a pelvic osteotomy. In all, 91 hips had open reduction alone and 621 had open reduction and pelvic osteotomy. Femoral shortening was performed in 221 hips. The mean age at the time of surgery was 2.1 years (1 to 6.5) and the mean follow-up time was 9.3 years (6 to 14). We used the Children's Hospital Oakland Hip Evaluation Score (CHOHES) to determine functional outcomes and the Severin classification was used to evaluate radiographic outcomes. The rate of avascular necrosis (AVN) and the need for a reoperation were also recorded and analyzed. RESULTS: In all 80% (570 hips) had good radiographic outcomes (Severin type I or II) and 87% had a CHOHES score of > 90 at final follow up. There was a 14% rate of AVN and only a 2% rate of redislocation. Better radiographic outcomes and lower reoperation rates were seen with patients who underwent both an open reduction and pelvic osteotomy. A trend was observed towards worse outcomes in older patients. CONCLUSIONS: There was a high rate of good clinical and radiographic outcomes at a minimum six-year follow-up in patients with late-presenting DDH who underwent open reduction. Those who underwent open reduction in combination with a pelvic osteotomy had a higher rate of good radiographic outcomes and a lower rate of complications, particularly reoperation.

7.
Acta ortop. mex ; 36(6): 367-372, nov.-dic. 2022. tab
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1533533

RESUMO

Abstract: Introduction: although pediatric orthopedic surgeons worldwide perform scoliosis surgery, the training received is variable and poorly understood. By surveying the European Pediatric Orthopedic Society (EPOS) and the Sociedad Latinoamericana de Ortopedia (SLAOTI), we aim to characterize this variability. Material and methods: in 2021, we distributed an anonymous online questionnaire to EPOS and SLAOTI. Results: 43% EPOS and 22% SLAOTI perform scoliosis procedures (p < 0.05). 18% EPOS and 2% SLAOTI performed > 35 procedures annually (p < 0.05). 70% EPOS and 27% SLAOTI received formal training in spinal deformity surgery (p < 0.005). Conclusions: results show significant differences in training and performance of scoliosis procedures between societies.


Resumen: Introducción: aunque muchos cirujanos ortopédicos pediátricos alrededor del mundo realizan cirugías para la escoliosis, el entrenamiento es variable y poco conocido. A través de encuestar a la Sociedad Europea de Ortopedia Pediátrica (EPOS) y a la Sociedad Latinoamericana de Ortopedia (SLAOTI) queremos caracterizar esta variabilidad. Material y métodos: distribuimos un cuestionario anónimo en 2021 a los miembros de EPOS y SLAOTI. Resultados: realizan las cirugías de escoliosis 43% de EPOS, en comparación con 22% de SLAOTI (p < 0.05); 18% de EPOS realizó > 35 cirugías al año, en comparación con 2% de SLAOTI (p < 0.05); 70% de EPOS y 27% de SLAOTI recibieron capacitación formal en cirugía de deformidades de la columna (p < 0.005). Conclusiones: los resultados de este estudio subrayan las diferencias en el entrenamiento de las cirugías de escoliosis entre diferentes sociedades.

8.
Clin Transl Oncol ; 19(12): 1469-1477, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28589434

RESUMO

PURPOSE: The aim of this study was to assess the feasibility and treatment outcome of intensity modulated radiation therapy with simultaneous integrated boost (SIB-IMRT) in locally advanced non-small cell lung cancer (NSCLC) patients. MATERIALS AND METHODS: A total of 64 NSCLC patients with stage IIB (3%), IIIA (36%), and IIIB (61%) were treated with concomitant (N = 47; 73%) or sequential (N = 9; 14%) chemotherapy between February 2009 and January 2014. Eight patients (13%) received RT alone. All patients received the same irradiation scheme using IMRT: prophylactic dose for mediastinum was 56 Gy at 1.65 Gy/fraction and SIB to macroscopic disease up to 68 Gy at 2 Gy/fraction. RESULTS: The median follow-up was 16 months (range, 1-70 months). The overall survival rate for all patients was 79% after 1 year and 46% after 2 years. Disease-free survival (DFS) was 81 and 45% after 1 and 2 years, respectively, resulting in a median DFS of 16 months. Multivariate analysis showed a statistically significant association between stage IIIB patients and a higher risk of mortality (HR 2.11; P = 0.019). In addition, T4 stage associated with higher risk of recurrence (HR 2.23; P = 0.024) while concomitant chemoradiation was associated with lower risk of any recurrence (HR 0.34; P = 0.004) No patient experienced grade ≥3 esophagitis and only 6 cases (9%) had grade 3 pneumonitis. Only having a higher lung volume was associated with higher risk of pneumonitis in the multivariate analysis (HR 16.21; P = 0.022). CONCLUSION: This study in advanced NSCLC patients shows that SIB-IMRT is an effective technique with acceptable toxicity, also when combined with chemotherapy.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/terapia , Quimiorradioterapia/efeitos adversos , Doenças do Esôfago/etiologia , Recidiva Local de Neoplasia/terapia , Radioterapia de Intensidade Modulada/efeitos adversos , Adenocarcinoma/patologia , Adenocarcinoma/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Grandes/patologia , Carcinoma de Células Grandes/terapia , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/terapia , Doenças do Esôfago/patologia , Feminino , Seguimentos , Humanos , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/terapia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Estudos Retrospectivos , Taxa de Sobrevida , Resultado do Tratamento
9.
Transplant Proc ; 48(2): 654-7, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27110023

RESUMO

This is a cohort, retrospective, comparative study of all liver transplant recipients from a single center, from May 1998 to July 2015. Patients were divided into two groups according to the type of Epstein-Barr viral load monitoring. For group I (1998-2007), polymerase chain reaction (PCR) was not available or it was only qualitative with limited access. For group II (2008-2015), we used periodically scheduled quantitative PCR in plasma and leukocytes, with aggressive tapering of immunosuppression as soon as viral replication was detected. Ninety-eight recipients were included, 41 (41.8%) were Epstein-Barr virus (EBV) - seronegative before liver transplantation (LT). EBV replication was confirmed in 74 patients (75.5%), being more frequent in seronegative (87.8%) than seropositive patients (66.6%). Eight recipients (8.1%) developed post-transplantation lymphoproliferative disorder (PTLD) on average at 14.3 months post-LT, seven of eight were <3 years at LT, four of eight were D+/R- for EBV, and all had post-LT EBV replication confirmed by PCR. PTLD was classified as lymphoma (n = 4), polymorphic polyclonal (n = 3), and lymphoid hyperplasia (n = 1). Five patients died, and three cleared PTLD after immunosuppression tapering or interruption. There were no significant differences in the etiology, age at LT (5.6 vs. 7.3 years, P = .069), patients <4 years (53.2% vs. 35.3%, P = .103), or EBV seronegative recipients (44.7% vs. 37.3%, P = .54); however, the incidence of PTLD decreased from 14.9% to 1.9% (P = .026), and graft rejection from 51.1% to 29.4% (P = .039). One- and 5-year patient survival rates were 94.7% and 85%, respectively, with no differences between groups. This strategy dramatically decreased the incidence of PTLD (14.9% vs. 1.9%), without increasing the incidence of rejection; therefore, we recommend that it should be used in the follow-up of all pediatric LT recipients.


Assuntos
Infecções por Vírus Epstein-Barr/diagnóstico , Transplante de Fígado/efeitos adversos , Transtornos Linfoproliferativos/prevenção & controle , Infecções Oportunistas/prevenção & controle , Criança , Pré-Escolar , Diagnóstico Precoce , Feminino , Rejeição de Enxerto/prevenção & controle , Herpesvirus Humano 4/isolamento & purificação , Humanos , Terapia de Imunossupressão/efeitos adversos , Linfoma/prevenção & controle , Masculino , Reação em Cadeia da Polimerase , Complicações Pós-Operatórias/prevenção & controle , Estudos Retrospectivos , Carga Viral
10.
Tex Heart Inst J ; 11(3): 296-300, 1984 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15227065

RESUMO

Endocardial fibroelastosis (EFE) in a mother and daughter are reported. This entity has a primary and secondary form. In this case, the 23-year-old mother died 11 months after delivery with findings of EFE. At age 3(1/2) years, the daughter was admitted in congestive heart failure and did not respond to medical management. The autopsy findings revealed EFE. Endocardial fibroelastosis in both mother and daughter is a very rare finding.

11.
JSLS ; 4(3): 247-50, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10987404

RESUMO

Acute epiploic appendagitis is not as rare as previously thought; but, since the presenting signs and symptoms are not specific, preoperative diagnosis has been rarely made. At the present time, a laparoscopic exploration of the peritoneal cavity will establish the correct diagnosis, and the treatment can be provided during the same procedure. Herein, a case of a 63-year-old female patient with acute abdominal syndrome caused by a necrotic epiploic appendix that was successfully diagnosed and treated laparoscopically is described. A review of the literature is made, as well.


Assuntos
Tecido Adiposo , Apendicite/diagnóstico , Apendicite/cirurgia , Laparoscopia/métodos , Abdome Agudo/etiologia , Doença Aguda , Apendicite/complicações , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Necrose , Anormalidade Torcional/complicações , Anormalidade Torcional/diagnóstico , Anormalidade Torcional/cirurgia , Resultado do Tratamento
12.
Rev Saude Publica ; 35(4): 380-4, 2001 Aug.
Artigo em Espanhol | MEDLINE | ID: mdl-11600928

RESUMO

OBJECTIVE: To assess the presence of Yersinia enterocolitica in otherwise healthy pigs slaughtered for human consumption. METHODS: One hundred pharyngeal tonsils were sampled in a slaughterhouse in the state of Mexico. The minimum sample size (n=100) was calculated based on a preliminary sample of 20 cases, which had 20% positive cases. The collected tonsil samples were inoculated in Rappaport broth, and Salmonella-Shigella and McConkey media. The biotyping identification process was based on biochemical and serological tests using O:3, O:8 and O:9 antisera. RESULTS: Twenty-two isolates were obtained. Most were biotype 1 (8 cases of O:3 and 8 cases of O:9), but 6 cases could not be serotyped. None of the isolates were of O:8 group. CONCLUSIONS: This was the first time that Y. enterocolitica serotypes were isolated from pig tonsils in Mexico. Its importance rely on the fact that the isolated serotypes are the most commonly found in public health problems.


Assuntos
Técnicas de Tipagem Bacteriana , Microbiologia de Alimentos , Carne/microbiologia , Yersinia enterocolitica/classificação , Animais , Estudos Transversais , Sorotipagem , Suínos/microbiologia , Yersinia enterocolitica/isolamento & purificação
13.
Pharmacol Biochem Behav ; 97(2): 213-21, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20705085

RESUMO

Depressive disorder involves emotional, cognitive, autonomic and endocrine alterations and also evidences support the role of stress in the development of this disorder. Because the hypothalamic-pituitary-adrenal axis is involved in the stress response with a concomitant rise in plasma corticoids, the present study compares the antidepressant effects of sertraline (10mg/kg, i.p.) on behavioral changes elicited by (i) restraint stress (2.5h/day for 13days) and (ii) corticosterone injections (30mg/kg, s.c., for 13days). Stressed animals, but not corticosterone-treated animals displayed anxiety behavior and a reduction in the acquisition of a conditioned avoidance response to 25% of control levels (8.0±2.2 vs. 31.7±3.2), being this effect partly sensitive to sertraline. Stressed, but not corticosterone-treated, animals displayed an increased escape failure compared with the control group (24.6%±3.5 vs. 1.6±0.7), an effect partly prevented by sertraline treatment (7.3%±2.0). Both stressed rats and corticosterone-treated rats showed an increase in immobility in the forced swim test, an effect prevented by sertraline. These results suggest that the altered behaviors elicited by stress and corticosterone can be explained by neural modifications that are sensitive to the sertraline antidepressant.


Assuntos
Antidepressivos de Segunda Geração/uso terapêutico , Corticosterona/farmacologia , Depressão/psicologia , Sertralina/uso terapêutico , Estresse Psicológico/psicologia , Glândulas Suprarrenais/efeitos dos fármacos , Animais , Ansiedade/psicologia , Aprendizagem da Esquiva/efeitos dos fármacos , Condicionamento Operante/efeitos dos fármacos , Corticosterona/sangue , Depressão/etiologia , Masculino , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Restrição Física , Estresse Psicológico/complicações , Natação/psicologia , Aumento de Peso/efeitos dos fármacos
15.
Phys Rev B Condens Matter ; 46(8): 4387-4394, 1992 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-10004193
16.
Philos Trans A Math Phys Eng Sci ; 361(1806): 947-64, 2003 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-12804223

RESUMO

A recently developed (Ponte Castañeda 2002 J. Mech. Phys. Solids 50, 737-757) 'second-order' nonlinear homogenization method is used to estimate the constitutive response of reinforced and other Bingham composites. For the special case of rigidly reinforced Bingham composites with overall isotropy (in two dimensions), the results show that the homogenized response of such materials is not strictly Bingham. Thus, instead of a purely linear incremental response beyond the relevant threshold (yield) stress, the response is strongly nonlinear just after yield and asymptotes to a purely linear incremental response only at sufficiently large stress or strain-rate levels. This phenomenon is linked to the presence of strong fluctuations of the strain-rate field in the composite at the onset of yield.


Assuntos
Simulação por Computador , Manufaturas , Modelos Teóricos , Anisotropia , Elasticidade , Movimento (Física) , Dinâmica não Linear , Estresse Mecânico
17.
J Nat Prod ; 51(5): 836-9, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-3204375

RESUMO

The new cucurbitacin glucoside 2-O-beta-D-glucopyranosylcucurbitacin F 25-acetate and arvenin I were isolated from the more polar fractions of the MeOH extract of Cigarrilla mexicana.


Assuntos
Medicina Tradicional , Plantas Medicinais/análise , Triterpenos/isolamento & purificação , México
18.
J Nat Prod ; 59(3): 323-6, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8882437

RESUMO

Investigation on the roots of Helianthella quinquenervis (Hook.) A. Gray (Asteraceae), led to the isolation of one new benzofuran (6-methoxy-tremetone (1)) and a new prenylacetophenone (4-beta-D-(glucopyranosyloxy)-3-[3-methoxy-trans-isopenten-1 -yl] acetophenone (3)). In addition, 6-hydroxy-3-methoxytremetone (2), encecalin (6), euparin (5), demethylencecalin (4), and angelic acid were obtained. Structural assignments of the isolated compounds were based on spectroscopic and spectrometric analysis. Natural products 1-4 showed marginal cytotoxicity against three human tumor cell lines [MCF-7, A-549, and HT-29]. Compounds 4 and 6 inhibited the radicle growth of Amaranthus hypochondriacus and Echinochloa crusgalli. Furthermore, substances 4-6 exhibited antifungal activity against Trichophyton mentagrophytes.


Assuntos
Antifúngicos/isolamento & purificação , Antineoplásicos Fitogênicos/isolamento & purificação , Inibidores do Crescimento/isolamento & purificação , Plantas Medicinais/química , Animais , Antifúngicos/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Artemia , Ensaios de Seleção de Medicamentos Antitumorais , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Inibidores do Crescimento/farmacologia , Células HT29 , Humanos , Testes de Sensibilidade Microbiana , Desenvolvimento Vegetal , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Raízes de Plantas/química , Plantas/efeitos dos fármacos , Células Tumorais Cultivadas , Estados Unidos
19.
Planta Med ; 65(5): 478-9, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17260274

RESUMO

A new triterpenoid, namely, lanost-25-en-3-beta-ol, and two known flavonoids (kaempferol-3,6-dimethyl ether and kaempferol 7- O-glucoside) were isolated from the aerial parts of Chamaesyce prostrate (Euphorbiaceae). The structure of the new compound was established based on spectral evidences.

20.
Educafrica ; (12): 153-71, 1985 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12268116

RESUMO

PIP: The information and population education and social and community welfare program drawn up by the International Labor Organization (ILO) aims at the improvement of the living conditions of workers through relating their incomes and needs to the basic needs of the family. The integration of voluntary associations in project activities can increase the effectiveness of messages; the multiplicity of information channels enlarges the scope and strenthens credibility insofar as these channels are accepted by the target groups. When it comes to determining the contents intended for groups such as trade unions, village committees, or cooperatives, a study of the area is undertaken to know their specific situation and the aspects concerning their population and social welfare problems. Population education provided by ILO deals with 2 primordial factors: 1) the improvement of working methods which will make it possible for individuals to improve of their health and living conditions while earning better incomes, and 2) the sharing all knowledge between men and women to encourage men to assume better responsibilities. The level of education of persons affected by projects is very different; they represent a complete range from the literate and semi-literate to the illiterate. Different units of production of educational equipment are being organized to meet material demand. In conclusion, educational and social welfare programs conform to the recommendations of the conference and will continue to draw on the World Population Action Plan to improve standards of living and quality of life for all people.^ieng


Assuntos
Educação , Serviços de Informação , Educação Sexual , Mudança Social , Planejamento Social , Seguridade Social , África , Países em Desenvolvimento , Economia , Emprego , Planejamento em Saúde , Mão de Obra em Saúde , Renda , Organização e Administração , Fatores Socioeconômicos , Ensino
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